﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using System.Web;

namespace ZFine.Code.Web
{
    public static class HtmlClear
    {
        public static string ClearHTMLTags(string HTML)
        {
            if (string.IsNullOrEmpty(HTML))
            {
                return null;
            }
            string[] Regexs ={
                        @"<script[^>]*?>.*?</script>",
                        @"<(\/\s*)?!?((\w+:)?\w+)(\w+(\s*=?\s*(([""'])(\\[""'tbnr]|[^\7])*?\7|\w+)|.{0})|\s)*?(\/\s*)?>",
                        @"([\r\n])[\s]+",
                        @"&(quot|#34);",
                        @"&(amp|#38);",
                        @"&(lt|#60);",
                        @"&(gt|#62);",
                        @"&(nbsp|#160);",
                        @"&(iexcl|#161);",
                        @"&(cent|#162);",
                        @"&(pound|#163);",
                        @"&(copy|#169);",
                        @"&#(\d+);",
                        @"-->",
                        @"<!--.*\n",
        };
            string[] Replaces ={
                            "",
                            "",
                            "",
                            "\"",
                            "&",
                            "<",
                            ">",
                            " ",
                            "\xa1", //chr(161),
                            "\xa2", //chr(162),
                            "\xa3", //chr(163),
                            "\xa9", //chr(169),
                            "",
                            "\r\n",
                            "",
                            ""
        };
            string s = HTML;
            for (int i = 0; i < Regexs.Length; i++)
            {
                s = new Regex(Regexs[i], RegexOptions.Multiline | RegexOptions.IgnoreCase).Replace(s, Replaces[i]);
            }
            s.Replace("<", "");
            s.Replace(">", "");
            s.Replace("\r\n", "");
            return s;
        }
         public  static string RemoveHTMLTags(string htmlStream)
       {
           if (htmlStream == null)
           {
               throw new Exception("Your input html stream is null!");
               return null;
           }

           /*
            *最好把所有的特殊HTML标记都找出来，然后把与其相对应的Unicode字符一起影射到Hash表内，最后一起都替换掉
            */

           //先单独测试,成功后,再把所有模式合并

           //注:这两个必须单独处理
           //去掉嵌套了HTML标记的JavaScript:(<script)[\\s\\S]*(</script>)
           //去掉css标记:(<style)[\\s\\S]*(</style>)
           //去掉css标记:\\..*\\{[\\s\\S]*\\}
           htmlStream = Regex.Replace(htmlStream,"(<script)[\\s\\S]*?(</script>)|(<style)[\\s\\S]*?(</style>)"," ", RegexOptions.IgnoreCase);
           //htmlStream = RemoveTag(htmlStream, "script");
           //htmlStream = RemoveTag(htmlStream, "style");

           //去掉普通HTML标记:<[^>]+>
           //替换空格:&nbsp;|&amp;|&shy;|&#160;|&#173;
           htmlStream = Regex.Replace(htmlStream,"<[^>]+>|&nbsp;|&amp;|&shy;|&#160;|&#173;|&bull;|&lt;|&gt;"," ", RegexOptions.IgnoreCase);
           //htmlStream = RemoveTag(htmlStream);

           //替换左尖括号
           //htmlStream = Regex.Replace(htmlStream, "&lt;","<");

           //替换右尖括号
           //htmlStream = Regex.Replace(htmlStream, "&gt;",">");

           //替换空行
           //htmlStream = Regex.Replace(htmlStream, "[\n|\r|\t]", "");//[\n|\r][\t*| *]*[\n|\r]
           htmlStream = Regex.Replace(htmlStream, "(\r\n[\r|\n|\t|]*\r\n)|(\n[\r|\n|\t| ]*\n)", "\r\n");
           htmlStream = Regex.Replace(htmlStream, "[\t| ]{1,}", "");

           return htmlStream.Trim();
       }



    

    }
}
